Phenotypic and Genotypic

Question 1

Phenotypic variation between species

Answer 1

• there are huge phenotypic differences between organisms of different species.
• This is because different species have different genes
• Different genes code for completely different proteins which make organisms of different species look and function differently.

Question 2

Phenotypic variation within a spcies?

Answer 2

• Phenotypic variation with a species is much more subtle
• This is because members of the same species have the same genes coding for the same proteins
• They can have different alleles

Question 3

Genetic variation within a species

Answer 3

• It is the alleles that gives rise to different eye colour and skin colour

Question 4

How do alelles work?

Answer 4

• It is the alleles that gives rise to different eye/skin/hair

Question 5

How do alleles work?

Answer 5

• The small difference in the sequences result in slightly different proteins being produced
• an allele - slightly different sequences of bases

Question 6

What are some traits that are monogenic?

Answer 6

• Controlled by a small number of genes with few/no alleles e.g. freckles, dimples
• Discontinous pattern of variation

Question 7

What are some traits that are polygenic?

Answer 7

• controlled by many genes with many alleles e.g. height, length of leaves, skin colour

Question 8

Evironmental modification of genetic traits

Answer 8

• phenotype of genetics traits can often be modified by the environment
• these traits are usually polygenic

Question 9

Chlorosis in plants

Answer 9

• a condition whereby a plant does not produce enough chlorophyll so the leaves appear yellow

Question 10

What is chlorosis caused by?

Answer 10

• environment

Question 11

Chlorotic plants

Answer 11

• have the correct genes to make chlorophyll but are unable to do so due to another one or more of the following: lack of light, magnesium deficieny, virus infection

Question 12

What is Etiolation in plants?

Answer 12

• plants that are grown in the dark will be yellow and grow long and spindly
• they do this to be able to reach the light

Question 13

which phenotypic characteristics in humans are affected by what we eat?

Answer 13

• body weight
• energy levels

Question 14

which genetic and environmental factors influence our weight?

Answer 14

• diet
• exercise